Mining-machine bit



March 18, 19246 1,487,198

N. K. BOWMAN MINING MACHINE BIT Filed Aug. 17. 1920 auoanto'z Patented Mar. 18, 1924.

NEWTON KJIBOWMAN, OF NORTH LAWRENCE, OHIO. A

MINING-MACHINE BIT.

Application filed August 17, 1920. Serial No. 404,108.

To all whom it may concern:

Be it known that I, NEWTON K. BOWMAN, citizen of the United States, residing at North Lawrence, in the county of Stark and State of Ohio, have invented certain new and useful Improvements in Mining-Machine Bits, of which the following is a specification.

This invention relates to an improved bit for mining machines and has as one of its principal objects to provide a bit employing a stock which may, if desired, be permanently fixed to the links of an ordinary mining machine chain and wherein a demountable cutting tooth will be provided to accomplish the actual cutting operation.

A further object of the invention isito provide an arcuate cutting tooth so "that the tooth will be adapted to withstandshearing strain thereon and wherein the tooth may be constructed of hardened material. for resisting wear.

A still further object of the invention is to provide a tooth having a curved cutting edge whereby the tooth will operate with a shearing action and wherein the sloping sides of the tooth will curve with said cutting edge to provide clearance for shavings.

And the invention has as a still further object to provide a tooth which may; be readily reversed end for end. v

Other and incidental objects will appear hereinafter.

In the drawing: 1 c

Figure 1 is a perspective view of my improved bit,

Figure 2 is a sectional view-particularly showing the mounting of the tooth,

Figure 3 is a rear perspective view showing the cutting tooth in detail,

Figure 4 is'a view similar to Figure. 2, showing a slight modification of the invention, and p Y Figure 5 is a transverse sectional view taken on the line 55 of Figure 4, looking in the direction of the. arrows.

Bits as now manufactured are formed of relatively soft material with the result'that the bits soon become dulled. To then sharpen the bits it is necessary to remove the bits from the endless chain of the mining to end of the tooth.

machine and the services of a blacksmith are usually required to accomplish the sharpening operation. Obviously, this not only results in expense but considerable delay. However, it has been found impracticable, due to the sizeof the-bits, to form said bits of hard material since this would involve an expense out of proportion to the advantage.

gained. The present invention, therefore, seeks to overcome these various difficulties.

Referring particularly to Figuresl, 2 and 3 of the di swings, I employ a stock 10 which is designed to supplant the usual bits of a mining machine chain and at its inner end portion is formed for connection to the links of said chain in the customary manner. Ifdesired, the stock 10 may be permanently fixed to the chain. At its outer end the stock is formed with a beveled face and at its forward edge is provided with an arcuate beveled seat 11 substantially V-shaped in cross section and having diverging sloping faces 12. In conjunction with the stock .I

employ an arcuate cutting tooth 13. As par-' ticularly shown in Figure 3, the tooth is longitudinally curvedto conform to the curvature of the seat 11 of the stock and is substantially V-shaped in cross section, having angularly disposed sides 14 which are curved to seat flat against the beveled faces 12 of said seat so that the apex of the seat abuts the crotch between said sides from end The tooth will thus be rigidly supported throughout its entire length by the stock and formed on the tooth at its forward face is a medial longitudinally curved or arcuate cutting edge 15 disposed opposite the apex of the seat '11.. The cutting edge 15 extends from end to end of the tooth and, as will now benot-ed, the tooth is formed with beveled divergent end faces which respectively define at each end of the tooth a substantially V-sha'ped cutting prow 16 terminating in a cutting point and having sharp side edges. From the outing edge 15, the sides l t slope to provide oppositely directed beveled faces 17 and dueto the curvature of said sides, thesefaces are curved longitudinally to conform to the curvature of the cutting edge. Formed in the sides of the tooth at their free edges are medial notches 18 and fitting over the tooth to embrace the outer end portion of the stock is a tooth bearing over said tooth medially thereof and threaded through the rear end of the clampisa set screw 20 adjustable to engage the rear edge of the clamp for firmly binding the tooth in position. Thus, as will be seen, the tooth will be rigidly connected to the stock while, at the same time, the tooth may be readily detached. should it become necessary,-the tooth may be easily removed and a new tooth substituted therefor, eliminating the work and delay of detaching the stock 10 from the chain of the mining machine. tooth, it may, without undue expense, be readily formed of hardened material for resisting wear and, also, this feature makes it readily possible to carry a supply of extra teeth'with eachmachine.

Attention is now directed to the fact that when the cutting tooth is clamped in place the end portions thereof extend forwardly from the stock 10 so that the cutting prow at one end of the tooth is exposed at the outer end of the stock. Thus, the cutting point of said prow will, when the tooth is in operation, lead the cutting edge 15 and due to the sharpness of said cutting point,

saidpoint will operate to readily sink or cut into the working face of the mine, per-f mitting the cutting edge 15 'to function. As

the tooth is advanced the sloping cutting.

edges at the sides of said prow will, as will be seen, operate against the mine face with a shearing action for loosening or cutting the coal in advance of the edge 15, thus facilitating the work of said edge, while the curved faces 17 of the sides of the tooth will operate to pry or force the coal cut by the cutting edges of the prow inwardly toward the inner end of the tooth at opposite sidesof the,edge 15. The edge 15 will, therefore,

in effect, work against loosened coal and since said edge is curved rearwardly away from each of the cutting points of the tooth, this edge will accordingly also. operate against the coal with a shearing action for cutting the coal. Where a straight cutting edge is employed upon a cutter of this'natiire, a

marked tendency is exhibited to merely mash or press into the coal so. that thecutter not only cuts slower but also a great deal more force is required to drive the cutter. However, by employing a curved cutting edge to extend in the rear of a sharp cutting point flanked by diverging cutting edges, as exemplified in the tooth of the Consequently,

Due to. the size of the present invention, the cutting action of the tooth is pronounced so that the greaterportion of the coal actually out falls away from the tooth in small lumps. The creation of what is commonly known as bug dust is thus greatly reduced and it has been found in -practice thatthe. coal out can be utilized for fuel-purposes. Furthermore, attention is directed to the fact that owing to the longitudinal curvature of the tooth, the tooth will better resist strain thereon incident to engagementof either of its cutting points witlrthe work and, as will be appreciated, when one of said points has. become dulled, the tooth may simply be reversed end for end. In this connection it is to be noted that the cutting edge 15 provides. in effect, 'a prolongation of the cutting points of the prows of the tooth so that as the ends of the tooth wear away, the presence of said edge will serve to maintain said cutting point-s sharp. Also, since the faces 17 of the sides of the tooth curve laterally inward fr'om the diverging cutting edges of the prows of the tooth. these edges will also be maintained sharp as the ends the work will of course, tend to shift the tooth inwardly upon the stock. However. due to the curvature of the seat 11 of said stock, the tooth cannot shift longitudinally of the stock in either direction without rising towardthe forward edge of the stock.

Consequently, even a slight longitudinal movement of the tooth will cause the tooth to jam between its scatv and the clamp 19 and .thus eliminate any looseness of the tooth. As will be appreciated, this feature provides an arrangement whereby the tooth willv at vall times be held firmly upon the stock whileaccidental displacement of the tooth will be prevented.

In Figures 4 and 5 of the drawings, 1 have illustrated a slight modification of the invention. In this'modification, I employ a stock 21 which, like the stock 10 is adapted for connection to a mining machine chain to supplant the ordinary bits thereon. This stock is beveled at itsouter end and at its forward edge is provided with an arcuate substantially ll-shaped seat 22 having converging sloping faces 23. In conjunction with the stock I provide an arcuate tooth 24. This tooth is, as particularly shown in Figure 5, substantially V-shaped in cross section, being formed with converging longitudinally curved sides 25. and is adapted to fit the seat of the stock seating flat therein. Thus, the sloping faces 23 of said seat will rigidly support the sides of the tooth while the apex between said sides will,

in the pre throughout its entire length, abut the crotch of the seat so that the tooth will be rigidly sustained from endto end thereof. The tooth is formed with divergent beveled ends which define, at each end of the tooth, a prow having a pair of cutting points 26 from which extend sloping side cutting edges and between these pairs of cutting points extend longitudinally curved or armate cuttingedges 27 provided by the free edges of the sides of the tooth. As will be appreciated, the cutting points 26 are adapted to function in a manner similar to the 'cuttin points 16 of the tooth disclosed erred form of the invention while the cutting edges 27 will function in a manner similar to the cutting edge 15. Formed in the sides of the tooth 26 are medial notches 28 and engaging over the tooth to embrace the stock 21 is a clamp 29, the sides of which engage in said notchesextending close to the sides of the stock, the sides 25 of the tooth overhanging the stock. At

its forward end, the clamp 29 is bent to form a rib 30 fitting the crotch between the sides of the tooth and threaded through the inner end of the clam isa set screw 31 ad-just able to engage, t e inner edge ofthe stock for tightly binding the tooth thereon. Thus, the tooth will be efiectively connected to the stock while, at the same time, the tooth may, when desired, be easily removed.

As will be seen, this modified structure possesses many structural features in com-.

inon with the preferred form of the invention and in view of the previousjexplana tion as to the operation of the' preferred construction, further description in connec'-' tion with the modified structure is believed unnecessary in this regard.

Having thus described the invention,

What is claimed as new is;

1. A bit for mining machines including a stock having an arcuate substantially V- ing over thetooth to embrace the stock and.

shaped seat, an alcuate substantially V- shaped tooth for said seat provided in the sides thereof with notches, a clamp engaghaving the sides thereof extending through said notches, and means adjustable upon the clamp to coact with the stock for binding the tooth against said seat.

1 2. A reversible tooth for mining machines comprising a body portion of substantially concavo convex form in cross section with its opposite ends converging in the direction of the convex side of the tooth to form diverging work engaging points.

3. A reversible tooth for mining machine comprising a segmental body portion having its opposite ends beveled to form terminal work engaging points and its side edges between said points formed 2 with notches for the reception of a fastenpoints.

ing device whereby the tooth maybe se-' 4. In a mining machine, a substantially crescent shaped cutting tooth. V-shaped in cross section and-having its opposite ends converging 2n the direction of the convex side of the tooth and terminating in diverging working points, the tooth being reversible end for end and the diverging walls of the tooth forming an arcuate cutting edge extending between said points.

5. In a mining machine, the combination with a stock for attachment to a chain link and having an arcuate seat, an arcuate double ended cutting tooth engaged in said seat, and means engaging the tooth between its ends and connecting the tooth with the stock whereby the tooth will be clamped in engagement with the stock for the major portion .of the length of the tooth and longitudinal movement; of the tooth will operate .to jam the tooth between said means and its seat, the tooth being reversible end for end upon the stock and the stock forming a backing for the ends of the cutting toot-h.

6. In a mining machine, a stock having a beveled end and a concave seat, a rever'si ble tooth of "substantially crescent shape engaging said seat and having its opposite ends beveled to conform to the beveled end of:the stock to provide terminal .working points, and means carried by the stock and engaging the tooth between the working points thereof for clamping the major portion o f' the tooth in engagement with its seat toform a backing for said working 7. In mining machine, the combination with a stock having a concave seat in one longitudinal edge thereof, of a substantially crescent shaped tooth engaging said seat. and provided with oppositely disposed working points and its side walls formed with notches, and a clamping device encircling the stock and tooth and fitting in said notches for detachably securing the tooth in position on the stock and holding the tooth to its seat for the major portion of the length of the tooth.

8. In a mining machine, the combination with a stock, of a reversible tooth having lateral wings bearing against the stock, and a clamping device engaging the tooth between the ends thereof for rigidly securing the tooth in position on the stock with the lateral wings bearing firmly against -said stock throughout the major portion of the length of. the tooth to form a. backing for the workingends of the tooth.

9. In a mining machine, the combination with a stock, of a reversible tooth having lateral wings, and means engaging the Lil tooth between the ends thereof for rigidly securing: the tooth in position on the stock with the lateral wing-s bearing firmly againstsaid steel: to pi'ovide a backing for the Working end of the tooth.

10. As a new zll'tlt'lOOf mami'lact-nre, a reversible double-ended mining machine bit; tooth provided with integral angularly disposed sides having their junction defining :1

cutting edge at the forward face of the tooth and formed with beveled end edges sloping rearwardly away from the ends of NEWTON K. BOWMAN. [L. 5.] 

